How to Make the Inner Coil of a Mainspring Smaller- Without Breaking It

Learn the Art of Reducing the Inner Coil of a Mainspring without Damaging It – Essential Guide

Are you a watch enthusiast interested in repairing your own timepieces? Or perhaps you’re a professional watchmaker looking to enhance your craft. Either way, learning how to reduce the inner coil of a mainspring without causing damage is a crucial skill to have. In this essential guide, we’ll take you through the art of reducing the inner coil step-by-step, ensuring your timepieces are repaired with precision and care. So, let’s get started!

Introduction

As a watch enthusiast, you understand the importance of maintaining the performance and longevity of your timepiece. One crucial aspect of watch maintenance is mainspring replacement, which requires adjusting the inner coil. Oversized inner coils can often make it challenging to hook the mainspring on the barrel arbor, leading to a damaged or broken mainspring. With the right technique and necessary tools, reducing the size of the inner coil can be done without damaging it. In this guide, we’ll explore the step-by-step process for reducing the inner coil, the importance of doing so, recommended tools and supplies, and tips for holding and manipulating the coil during the adjustment process.

How to Reduce the Inner Coil of a Mainspring

The video linked below demonstrates a technique for reducing the size of the inner coil of a mainspring without breaking it. The method requires a soldering iron or an alcohol lamp. Step-by-Step Process:

  1. Clamp the mainspring arbor in a vise using nylon jaws or a regular vise with soft aluminum jaws to avoid damaging the arbor.
  2. Put the hook of the mainspring in the barrel arbor and move it so that the mainspring is stretched out.
  3. Heat the soldering iron or alcohol lamp.
  4. Place the hot tip of the soldering iron or the flame of the alcohol lamp near the inner coil until it starts to turn red.
  5. Use tweezers to hold and manipulate the coil while it’s still hot and malleable.
  6. Once the coil has cooled down, it will have a smaller diameter, making it easier to hook onto the mainspring barrel arbor.

Why Reducing the Inner Coil is Important

Reducing the size of the inner coil is essential because it ensures a proper fit of the mainspring on the barrel arbor. An oversized inner coil can make it difficult to hook onto the arbor, which can lead to a damaged or broken mainspring. A broken mainspring can cause significant harm to your watch’s movement, resulting in costly repairs and extended downtime.

Recommended Tools and Supplies

The following tools and supplies are recommended for reducing the size of the inner coil: Tools:

  • Soldering iron or alcohol lamp.
  • Tweezers.
  • Nylon jaws or soft aluminum vise jaws.
  • Barrel arbor holder.

Supplies:

  • Denatured alcohol for cleaning.
  • Brass or bronze mainspring winder.
  • Mainspring replacement kit.

These tools and supplies are available on Amazon. The links are provided below.

Tips for Holding and Manipulating the Coil

Here are some tips for holding and manipulating the coil during the adjustment process:

  • Keep the heat source close to the coil for only a short time.
  • Use tweezers to hold the coil while it’s hot.
  • Don’t put too much pressure on the coil.
  • Use a barrel arbor holder to keep the barrel arbor steady while attaching the mainspring.
  • Use denatured alcohol to clean the mainspring before installation.

 

 

WATCHMAKING TOOLS SEEN IN THIS VIDEO ARE AVAILABLE ON AMAZON!

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Bergeon Screwdriver Set

 

Dumont Tweezer #3

 

Bergeon Springbar Tool

 

Bergeon Case Opening Ball

 

Bergeon Presto Hand Removal Tool

 

Bergeon Movement Holder

 

Horotec Hand Setting Tools

 

Rodico

 

Bergeon Blower

 

Bergeon Case Opening Knife

 

Bergeon Quick Service Kit

 

Ultrasonic Cleaning Machine

 

Amscope Microscope

 

Multifunction Timegrapher

 

Sanding Sticks

 

 

CAMERAS AND AUDIO:

 

Main Camera, Sony A7III

 

Secondary Camera, Sony RX100

 

Tertiary Camera, Sony A6400

 

Main Macro Lens, Sigma 70mm f/2.8

 

Secondary Macro, Laowa 100mm f/2.8

 

Camlink 4k Video Converter

 

Shure MV7 Microphone

 

Audio Recorder, ZOOM H6

 

Small Sirui Tripod

 

Sirui Tripod Head for Overhead Camera

 

COMPUTER STUFF:

 

Apple Macbook Pro

 

Synology NAS

 

Seagate HDDs for NAS

 

Samsung Portable Drive

 

FAQs

Q: Can this technique be done with any mainspring? A: The technique can be used with brass or bronze mainsprings. Q: Can I use a regular vise to hold the mainspring arbor? A: It’s recommended to use a vise with aluminum jaws or nylon jaws to avoid damaging the arbor. Q: Will reducing the inner coil of the mainspring affect the overall performance of my watch? A: No, it won’t affect the overall performance of your watch. Q: How long does it take for the coil to cool down after the reduction process? A: It takes approximately 30 seconds to one minute for the coil to cool down. Q: Can I perform mainspring replacement on my own? A: Mainspring replacement requires a specialized set of skills and knowledge. It’s recommended to seek the assistance of a professional watchmaker.

Conclusion

Reducing the inner coil of a mainspring is an essential part of watch maintenance, and with the right technique, tools, and supplies, it can be done without damaging the mainspring. By using the step-by-step process outlined in this guide, watch enthusiasts can maintain the performance and longevity of their timepieces. Don’t forget to use the recommended tools and supplies and remember to seek professional assistance for mainspring replacement if needed.

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